Cable Technology Meets Requirements for High Data-Rate Applications

W. L. Gore & Associates has introduced the next
generation in cable technology for high data-rate applications. This technology
consists of a new differential cable design with lower SCD21 (differential-to-common-mode
conversion) and a very high level of signal fidelity. Additionally, it provides
the only cable solution that addresses the degradation in performance caused by
SCD21. Engineered for InfiniBand and other high data-rate applications, this
new design has yielded SCD21 values that are typically below -40 dB and
consistently well below -25 dB across a 20 GHz bandwidth.

SCD21 is a differential s-parameter matrix element that
represents the unwanted conversion between differential mode and common mode in
a transmission line. This conversion reduces the signal’s energy in
differential mode, which causes unpredictable phase delays and skin-effect
losses across frequencies. In coupled differential cables, the conversion
results in differential-mode jitter. If these effects are not taken into
account, the signal may not be recovered.

According to Russ Hornung, Gore Cable Product Manager, “In
the past year, we have seen more applications employing advanced serializer/deserializer
(SERDES) technologies and signal recovery processing that should include a
specification for SCD21 performance; however, SCD21 currently is not addressed
in most manufacturer or industry specifications. This new technology allows for
faster digital data rates that can exceed 20 Gbps without signal integrity
being compromised.”

Available in cables with smaller gauge sizes (AWG24 to
AWG32), Gore’s low SCD21 technology allows for very precise cancellation of
signals of equal amplitude and differential polarity, with very little phase
difference between the differential legs. Using proprietary materials for the
cable jacket and dielectric has enabled Gore to engineer the smallest, most
flexible cables for high-speed data rate applications.